Harrassment by flat owners association

I own two flats in kerala one with 589 sqft and other with 250 sqft., in same complex under same owners association.As per construction agreement signed between all owners including me separately with builder, the maintenance charges to be paid is proportionate to undivided share of each flat. But the association wanted me to pay same maintenance charge to both the flats. So I did not pay maintenance charge for 250 sqft flat informing that I am ready to pay only proportionate to share as per my share. But association was not ready to accept and charging heavy penalty for default. But this year when I paid the maintenance charge for 589 sqft flat that amount is accounted for the first arrears of 250 sqft flat. So the legal question is 1. whether the construction agreement terms of proportionate share can be violated by association whose members signed and agreed this terms with builder. Incidently this proportionate share principle is written in Kerala Apartment ownership act 1983 also. 2. when defaulted payment for one flat due to disputed reasons can they account my payment to other flat for disputed flat without my permission? Kindly give a considered reply and remedy Thanks Chandran